1. Technical Field
The present disclosure relates to the field of gamma cameras used in the area of nuclear medicine and, more particularly to collimator storage devices, exchange devices and carts.
2. Background of Related Art
Nuclear or scintillation cameras (also called gamma cameras) are responsive to radiation emitted from a radiopharmaceutical injected into a patient during an imaging study. A radiopharmaceutical is typically selected that will target a particular organ or tissue of interest. In computed tomography studies, a detector head (or pair of heads) revolves around the patient and collects the emissions at various angles in order to generate an image of the targeted organ or tissue. In total body studies, the detectors may translate at a fixed or variable altitude along the patient.
In Emission Computed Tomography (ECT) studies, the image data collected at each angle is merged together into a database that is representative of a three dimensional image of the targeted organ or tissue by a mathematical procedure called reconstruction tomography. A computer process and system perform the image data collection and tomography, and the resultant images may be displayed in a variety of fashions on a computer controlled display screen. Gamma camera detectors are also used in many types of studies that do not employ tomography for image generation, such as total body studies.
Each detector head of a gamma camera utilizes a collimator placed in front of the detector mechanism to respond to the incident emissions. The collimator is a device for collimating the incident radiation emissions and for filtering out certain types of unwanted radiation emissions. A collimator is typically manufactured from lead material and is composed of an array of parallel tubes and as such resembles a lead “honey comb.” Each individual collimator may weigh from 100 to 250 pounds or more and is mounted on the receiving end of the gamma camera detector to cover the imaging surface. Each collimator must be securely fastened to the detector head during gamma camera studies to prevent collimator separation from the imaging surface as the detector heads revolve or rotate.
Different collimators have particular characteristics suited to the patient study and the energy of the radiation emissions from the ingested radiopharmaceutical. For instance, some collimators are better suited for gamma studies of a given energy range, a given emission exposure duration, or a given radiopharmaceutical.
Typically, a nuclear camera includes a family of collimators. Relatively thicker collimators with small bores provide higher resolution. Relatively thinner collimators and collimators with larger bores provide higher count rates. Collimators whose bores are angled are used for magnification and reduction imaging. Specialized collimators that focus on two displaced regions of the subject are also used.
In many instances, the collimators need to be changed depending on the particular procedure being performed and to maintenance purposes. To change the collimators, the operator moves the detector heads to the appropriate collimator changing position. The operator then rolls in a collimator holding cart, which supports the currently installed collimators as they are disconnected. The cart is then used to transport the collimators to a storage location where it is further used to pick-up the proper set of collimators. The appropriate set of collimators on the cart are wheeled up to the detector heads and manually mechanically coupled. This operation typically requires 10-15 minutes of operator time.
Accordingly, a continuing need exists for carts or carriages for facilitating the removal, replacement and/or exchange of collimators from a nuclear camera and the like.